KR101400554B1 - Doble sided adhesive tape - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer having a specific degree of cure using an acrylic syrup on a rigid substrate.
Specifically, the double-sided pressure-sensitive adhesive tape of the present invention comprises: a substrate; And a pressure-sensitive adhesive layer comprising acrylic syrup, a polyfunctional acrylic group-containing curing agent, and a photoinitiator, wherein the pressure-sensitive adhesive layer is formed on both sides of the substrate, and the gel fraction after curing of the pressure-sensitive adhesive layer is 30 to 50% .

Description

DOBLE SIDED ADHESIVE TAPE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer having a specific degree of cure using an acrylic syrup on a rigid substrate.

Recently, a PDA, a mobile communication terminal, or a navigation system for a vehicle have formed a large market. These electronic devices are required to continuously develop technologies for thinning, lightening, low power consumption, high resolution, and high brightness.

In particular, a touch screen to be applied to an electronic apparatus having a touch screen or a touch panel switch on an input operation section is changed from a resistive film type to a reinforced glass type by an electrostatic method. Various conductive films and adhesive films Respectively. In addition, the main body of the electronic device is introduced not only into various plastics but also metal materials. In the upper part of the LCD panel part, various kinds of surface treatment are performed in addition to the polarizing plate to improve the visibility.

In this field, double-sided pressure-sensitive adhesive tapes are required for attaching the surfaces of different materials, and it is a reality that a pressure-sensitive adhesive layer is introduced into both sides of a rigid film such as conventional PET. There is a problem that the touch screen and the main body of the apparatus or the LCD panel are separated from each other when an electronic device using a rigid film such as PET is impacted from the outside.

The touch screen needs to be changed from a light film type to a heavy tempered glass to improve the impact resistance, and a stable adhesion performance is gradually required regardless of the type of the adherend. Double - sided adhesive tapes to be used in electronic devices are very thin and less than 2 mm in line width to adhere upper and lower, and adhesion is also important, but stability is also recognized in actual endurance reliability conditions.

In accordance with this demand, a double-faced adhesive tape filed by Nitto Denko Kogyo Co., Ltd. has a pressure-sensitive adhesive layer on both sides of a foam substrate and has a total thickness of 250 microns or less. Particularly, in this double-faced pressure-sensitive adhesive tape, 30 parts by weight of rosin ester is used as an adhesive agent for the pressure-sensitive adhesive layer (Patent Document 1).

In addition, a double-sided adhesive tape filed by Dai-ichi Kogyo Co., Ltd. discloses an acrylic pressure sensitive adhesive composition containing an acrylic copolymer having a predetermined composition and a polymerized rosin ester tackifier (Patent Document 2).

The above-mentioned Patent Documents 1 and 2 have a pressure-sensitive adhesive layer on both sides of a foam base material. The pressure-sensitive adhesive layer can provide waterproofness, impact resistance and followability depending on the characteristics of the foam, Although the adhesive agent may be added to improve the adhesive property, there is a problem that the reliability of the durability can not be substantially guaranteed.

[Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2010-155969

Patent Document 2: Japanese Patent Application Laid-Open No. 2010-260880

DISCLOSURE Technical Problem The present invention has been made to overcome the problems presented in the conventional double-sided pressure-sensitive adhesive tape, and it is an object of the present invention to provide a double-sided pressure-sensitive adhesive tape for fixing a touch screen excellent in adhesion and durability.

In order to achieve the above object, the double-sided adhesive tape of the present invention comprises: a substrate; And an adhesive layer comprising an acrylic syrup, a polyfunctional acrylic group-containing curing agent, and a photoinitiator, wherein the adhesive layer is formed on both sides of the substrate, and the gel fraction after curing of the adhesive layer is 30 to 50 wt% .

The double-sided pressure-sensitive adhesive tape according to the present invention has an excellent adhesive strength, an excellent durability and a high reliability.

1 is a cross-sectional view of a double-faced pressure-sensitive adhesive tape according to the present invention.
2 is a flowchart schematically showing a method for producing a double-sided pressure-sensitive adhesive tape according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Double-sided adhesive tape

Hereinafter, the double-faced pressure-sensitive adhesive tape of the present invention will be described in detail with reference to Fig. The double-faced pressure-sensitive adhesive tape (100) of the present invention comprises a substrate (10); And an adhesive layer (20) comprising an acrylic syrup, a polyfunctional acryl group-containing curing agent and a photoinitiator, wherein the gel fraction of the adhesive layer after curing is 30 to 50 wt%.

materials

The double-faced pressure-sensitive adhesive tape (100) of the present invention is characterized by including a rigid base material (10).

The rigid substrate 10 of the present invention is not particularly limited as long as it is a substrate having strength for durability, and a general plastic substrate such as a polyester film, for example, polyethylene terephthalate, can be used.

Adhesive layer

The adhesive layer 20 of the present invention is laminated on the flat both surfaces of the above-described rigid substrate 10 as shown in Fig.

The adhesive layer 20 of the present invention comprises a) acrylic syrup, b) a polyfunctional acrylic group-containing curing agent, and c) a photoinitiator.

In the present invention, the a) acrylic syrup preferably comprises an alkyl (meth) acrylic acid ester monomer containing a (meth) acrylic ester monomer, particularly an alkyl group having 1 to 20 carbon atoms.

Specific examples of the (meth) acrylic ester monomer include methyl acrylate, ethyl acrylate, propyl acrylate, butyl (meth) acrylate, but are not limited to, butyl acrylate, hexyl (meth) acrylate, 2-ethylhexyl (acrylamide), ethylhexyl acrylate, lauryl acrylate, stearylacrylate, an alkyl (meth) acrylate such as octadecyl acrylate, isooctyl acrylate, isononyl acrylate, isodecyl acrylate, or isobonyl acrylate. Acrylic acid ester monomers, and they may be used alone or in combination of two or more.

The acrylic syrup of the present invention may contain, in addition to the alkyl (meth) acrylic acid ester monomer, a (meth) acrylic acid aryl ester such as phenyl (meth) acrylate or benzyl (meth) acrylate; (Meth) acrylic acid alkoxyalkyl such as methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate or ethoxypropyl (meth) acrylate; (Meth) acrylic acid and (meth) acrylic acid alkali metal salt; Di (meth) acrylic acid esters of ethylene glycol, di (meth) acrylic acid esters of diethylene glycol, di (meth) acrylic acid esters of triethylene glycol, di (meth) acrylic acid esters of polyethylene glycol, di Di (meth) acrylic acid esters of (poly) alkylene glycols such as esters; (Meth) acrylic acid esters such as trimethylolpropane tri (meth) acrylate or trimethyl propane tri (meth) acrylic acid ester.

On the other hand, a) acrylic syrup according to the present invention is a polar monomer copolymerizable with a (meth) acrylic ester monomer, wherein the monomer having a carboxyl group, a monomer containing a hydroxyl group, a monomer containing a glycidyl group, a monomer containing nitrogen, a carboxylic acid vinyl ester, Monomers, and the like.

The polar monomers serve to impart cohesive force to the resin or the molding through secondary processing and to control the adhesive force.

More specifically, as the polar monomer copolymerizable with the (meth) acrylic ester monomer, a monomer containing a carboxyl group such as (meth) acrylic acid, maleic acid, or fumaric acid; (Meth) acrylate, hydroxy (meth) acrylate, hydroxy methyl acrylate, hydroxy (meth) ethyl acrylate, and hydroxy propyl a monomer containing a hydroxyl group such as acrylate, or hydroxy (butyl) acrylate; Monomers containing a glycidyl group such as glycidyl (meth) acrylate; Monomers containing a nitrogen component such as acryl amide or acrylonitrile; And carboxylic acid vinyl esters such as vinyl acetate. Further, a styrene-based monomer such as styrene or benzoyl (meth) acrylate may be used as the unsaturated monomer.

The proportion of the (meth) acrylic ester monomer and the polar monomer copolymerizable therewith is preferably 30 parts by weight or less, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the (meth) acrylic ester monomer, Do not. If the content exceeds 30 parts by weight, the flexibility of the composition may be deteriorated.

Meanwhile, the acrylic syrup according to the present invention may further comprise a chain transfer agent, which may be an organic compound containing a thiol group (-SH group).

Specifically, alkyl mercaptans such as ethyl mercaptan, butyl mercaptan, hexyl mercaptan, or dodecyl mercaptan; Thiophenols such as phenyl mercaptan or benzyl mercaptan; Carboxyl group-containing mercaptans such as thioglycolic acid, 3-mercapto propionic acid, or thiosalicylic acid; Hydroxyl group-containing mercaptans such as 2-mercapto ethanol or 3-mercapto-1,2-propanediol; Or mercaptans having two or more functional groups in combination such as pentaerythritol tertracis (3-mercapto) propionate, or the like, or two or more kinds of Can be mixed and used.

The chain transfer agent is preferably used in an amount of 5 parts by weight or less, more preferably 0.005 to 5 parts by weight based on 100 parts by weight of the (meth) acrylic ester monomer, but is not limited thereto. If the amount of the chain transfer agent used is more than 5 parts by weight, the polymerization rate is slowed down and the molecular weight is too low, thereby deteriorating the physical properties of the final product.

In addition, a) acrylic syrup according to the present invention may comprise a reaction initiator. The reaction initiator is preferably an azo compound or a peroxide. The reaction initiator used in the present invention is not particularly limited, but an azo compound or a peroxide compound is preferably used.

The azo type initiator may be at least one selected from the group consisting of 2,2'-azobis (isobutylonitrile), AIBN, 2,2'-azobis (2-methylbutylonitrile) Azobis (2-methylbutyronitrile)], 2,2'-azobis (2,4-dimethylvaleronitrile), or 2,2'- Azobis (4-methoxy-2,4-dimethylvaleronitrile) may be used as the azo compound.

The peroxide initiator may also be selected from the group consisting of Di-tert-Butyl peroxide, Dilauroyl peroxide (LPO), Dibenzoyl peroxide (BPO), m-Tolyl benzoyl peroxide m-toluyl benzoyl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, didecanoyl peroxide, distearyl peroxide Tert-butyl peroxyneodecanoate, tert-amyl peroxypivalate, di-3-methoxybutyl peroxydicarbonate, di-3- methoxybutyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, tert-butyl isopropyl monoperoxycarbonate and the like.

The initiators may be used alone or in combination of two or more. The content of the initiator is 0.0001 to 1 part by weight, preferably 0.0005 to 0.1 part by weight, more preferably 0.001 to 0.05 part by weight based on 100 parts by weight of the (meth) acrylic ester monomer composition. When the content of the initiator is less than 0.0001 part by weight, not only the initiation efficiency is lowered but also the reaction is continuously maintained. When the amount is more than 1 part by weight, the temperature control in the reactor becomes difficult.

The acrylic syrup according to the present invention is preferably partially polymerized at a conversion of 5 to 20%, and may be diluted with a new monomer as required after the reaction.

When the partial polymerization conversion ratio is less than 5%, there may be a problem in coatability due to a low viscosity. When the conversion rate exceeds 20%, the workability is lowered due to the occurrence of steam in the process part after the double- do.

The weight average molecular weight of the partially polymerized a) acrylic syrup is preferably 800,000 to 2,000,000. When the weight average molecular weight is less than 800,000, workability is lowered due to the generation of steam, and when the weight average molecular weight is more than 200,000, it is difficult to exhibit high adhesive performance.

The pressure-sensitive adhesive layer (20) of the present invention is characterized by containing b) a polyfunctional acrylic group-containing curing agent.

The bifunctional polyfunctional acrylic group-containing curing agent preferably has two functional groups, and examples thereof include polypropylene glycol diacrylate, polyethylene glycol diacrylate, tetraethylene glycol diacrylate, ethylene oxide-modified bisphenol A diacrylate, Diethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, butanediol diacrylate, 1,6-hexanediol diacrylate, and the like.

The content of the bifunctional polyfunctional acrylic group-containing curing agent is preferably 0.01 to 0.1 parts by weight per 100 parts by weight of the reactive monomer of the acrylic syrup. If the content thereof is less than 0.01 part by weight, the endurance reliability may be a problem. If the content is more than 0.1 part by weight, high adhesive performance is deteriorated.

The adhesive layer (20) of the present invention is characterized by comprising c) a photoinitiator.

In the present invention, as the photoinitiator (c), any of them can be used as long as it can initiate polymerization reaction through ultraviolet irradiation or the like.

Examples of the photoinitiator that can be used in the present invention include alpha -hydroxyketone-based compounds (e.g., IRGACURE 184, IRGACURE 500, IRGACURE 2959, DAROCUR 1173, Ciba Specialty Chemicals); Phenylglyoxylate-based compounds (such as IRGACURE 754, DAROCUR MBF; Ciba Specialty Chemicals); Benzyldimethylketal-based compounds (such as IRGACURE 651; Ciba Specialty Chemicals); alpha -aminoketone-based compounds (e.g., IRGACURE 369, IRGACURE 907, IRGACURE 1300; Ciba Specialty Chemicals); Monoacylphosphine based compounds (MAPO) (e.g. DAROCURTPO; Ciba Specialty Chemicals); Bisacylphosphine compounds (BAPO) (e.g., IRGACURE 819, IRGACURE 819DW; Ciba Specialty Chemicals); Phosphine oxide-based compounds (such as IRGACURE 2100; Ciba Specialty Chemicals); Metallocene compounds (such as IRGACURE 784; Ciba Specialty Chemicals); Iodonium salts (e.g. IRGACURE 250; Ciba Specialty Chemicals); And mixtures of at least one of the foregoing (for example DAROCUR 4265, IRGACURE 2022, IRGACURE 1300, IRGACURE 2005, IRGACURE 2010, IRGACURE 2020, Ciba Specialty Chemicals). In the present invention, one or more selected from the above group may be used, but the present invention is not limited thereto.

The content of the c) photoinitiator is suitably 1 to 10 parts by weight relative to 100 parts by weight of the reactive monomer of the acrylic syrup. If the content is less than 1 part by weight, high adhesive performance is deteriorated, and if it exceeds 10 parts by weight, endurance reliability may be a problem.

On the other hand, the acrylic syrup composition of the present invention may further comprise, in addition to the above-mentioned components, a thermosetting additive, One or more additives may suitably be included.

Method of manufacturing double-sided adhesive tape

2 is a flowchart schematically showing a method for producing a double-sided pressure-sensitive adhesive tape according to the present invention.

As shown in the drawings, the method for producing a double-faced pressure-sensitive adhesive tape according to the present invention includes the steps of forming an adhesive layer including an acrylic syrup, a multi-functional acryl group-containing curing agent, and a photoinitiator on a release film or a release paper (S100); Performing corona treatment on both surfaces of the rigid substrate (S200); And forming the adhesive layer on both surfaces of the rigid substrate (S300).

First, in step S100 of forming a pressure-sensitive adhesive layer containing an acrylic syrup, a polyfunctional acrylic group-containing curing agent and a photoinitiator on a release film or release paper, the above-described pressure-sensitive adhesive composition containing an acrylic syrup is applied onto a release film or release paper Followed by curing to form an adhesive layer.

At this time, the pressure-sensitive adhesive composition can be prepared by appropriately blending the above-mentioned components by a method known in the art. In the present invention, it is preferable that the acrylic syrup is made into a non-solvent type so that the solid content concentration of the acrylic syrup becomes 100% in this process.

In this case, the acrylic syrup is made of a non-solvent type so that the process efficiency can be improved, and a film having a uniform thickness deviation can be produced without bonding of a fish eye or the like. Further, by eliminating the use of a solvent, the production of a thick film can be facilitated, and a solvent evaporation step is not required, so that a dryer such as a drying oven can be omitted in actual facilities. In addition, omission of the solvent volatilization process eliminates the need for environmental facilities due to solvent volatilization and does not cause environmental pollution problems after the process environment or process.

The viscosity of the acrylic syrup to be used in this step S100 is preferably controlled to be in a range of 100 to 10,000 cps as described above in order to proceed an efficient process.

Meanwhile, in this step S100, the pressure-sensitive adhesive composition prepared in the above-described manner is formed. At this time, the method of forming the pressure-sensitive adhesive composition is not particularly limited, and for example, a casting method can be applied.

Specifically, the pressure-sensitive adhesive composition is coated on a release film or release paper by a conventional means such as a bar coat, a knife coat, a roll coat, a spray coat, a gravure coat, a curtain coat, a comma coat and / Can be performed. By performing the film formation in this manner and conducting the ultraviolet ray irradiation process, a film having improved properties such as thickness uniformity, high temperature dimensional stability, cutability, and transparency can be obtained.

Specifically, in the present invention, it is possible to produce an acrylic film by casting the above-mentioned pressure-sensitive adhesive composition on a release film or a release paper in a liquid state, and then forming the film into a film. When such a method is used, the stress applied to the pressure-sensitive adhesive composition at the time of film formation is minimized, and the change of dimension due to the passage of time or heating does not occur. In addition, the removal of solid impurities is easy, and the occurrence of fish eyes and the like in the film thus formed is suppressed, whereby the film thickness uniformity and the thickness accuracy can be improved. In addition, when the above method is applied, the stress relaxation property of the film can be improved, and the residual stress generated when attached to the adherend can be quickly resolved.

On the other hand, the type of the releasing film or releasing paper that can be used in the film forming step is not particularly limited, and for example, a normal plastic substrate (for example, PET substrate) subjected to the releasing treatment, a paper, a nonwoven fabric, .

Next, the formed pressure-sensitive adhesive composition is cured by irradiating ultraviolet rays to thereby polymerize the acrylic syrup to form an adhesive layer.

The method of irradiating ultraviolet rays is not particularly limited and may be carried out by means of, for example, a high-pressure mercury lamp, a non-electrode lamp, or a xenon lamp.

In this case, ultraviolet light (wavelength: 230 nm to 400 nm) having an illuminance of 5 to 200 mW / cm ² can be irradiated for about 2 seconds to 20 minutes. Also, in this step, the light amount of ultraviolet light can be controlled within a range of 4 to 2,000 mJ / cm ² .

However, the ultraviolet irradiation condition is only an example of the present invention. In other words, in the present invention, the ultraviolet irradiation conditions can be freely changed within a range to such an extent that sufficient curing of the acrylic syrup can be achieved without compromising the physical properties.

Next, the step of performing corona treatment on both surfaces of the rigid base material (S200) is to modify the surface of the base material, thereby forming a surface roughness on the base material and removing the foreign matter to form the adhesive layer 20 do.

Finally, the double-sided pressure-sensitive adhesive tape can be manufactured through the step of forming the pressure-sensitive adhesive layer on both surfaces of the substrate (S300).

The respective embodiments related to the double-sided adhesive tape according to the present invention and the comparative examples not complying with the manufacturing method of the present invention are listed below for comparison. This comparison will describe the features and advantages of the present invention. Further, the present invention is not limited by the embodiments described below.

Example  And Comparative Example

Example  One

95 parts by weight of 2-ethylhexyl acrylate and 5 parts by weight of acrylic acid were added to a 1-liter glass reactor under the conditions of 100 parts by weight of the acrylic copolymer resin to be produced and partially thermally polymerized to obtain a copolymer having a solid content of 18%, a weight average molecular weight of 700,000, acrylic resin syrup (type A) having a weight-average molecular weight (cps) of 20,000 was prepared.

Subsequently, 2 parts by weight of Irgacure 651 (IRGACURE 651) as a photoinitiator and 0.03 part by weight of 1,6-hexanediol diacrylate as a crosslinking agent were added to the acrylic resin syrup (type A), and the mixture was thoroughly stirred and mixed. Then, the mixture was degassed under reduced pressure using a vacuum pump, and then coated on a polyester release film with a knife coater so as to have a thickness of 70 m after being cured. Using a black light lamp in a nitrogen atmosphere, Was irradiated with ultraviolet rays for about 3 minutes to prepare a film having an adhesive layer. And then laminated on both sides of 12 占 퐉 Black PET to produce a double-sided pressure-sensitive adhesive tape.

Example  2

The double-faced pressure-sensitive adhesive tape of Example 2 was prepared in the same manner as in Example 1, except that an acrylic resin syrup (type B) was used.

The acrylic resin syrup (type B) was prepared by mixing 60 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of isobornyl acrylate and 20 parts by weight of 2-hydroxyethyl acrylate with 1 liter of glass based on 100 parts by weight of the acrylic copolymer to be produced And subjected to partial polymerization as heat to prepare a solid having a solid content of 16%, a molecular weight of 110,000, and a viscosity of about 3,000 cps.

Example  3

The double-faced pressure-sensitive adhesive tape of Example 3 was prepared in the same manner as in Example 2, except that 5 parts by weight of a photoinitiator was used.

Example  4

The double-faced pressure-sensitive adhesive tape of Example 4 was prepared in the same manner as in Example 2, except that 0.08 part by weight of a curing agent was used.

Example  5

The double-faced pressure-sensitive adhesive tape of Example 5 was prepared in the same manner as in Example 2 except that the finished acrylic resin syrup (type B) had a solid content of 5%, a molecular weight of 800,000, and a viscosity of 100 cps.

Example  6

The double-faced pressure-sensitive adhesive tape of Example 6 was prepared in the same manner as in Example 2 except that the finished acrylic resin syrup (type B) had a solid content of 20%, a molecular weight of 2 million, and a viscosity of 10,000 cps.

Comparative Example  One

Comparative Example 1 was prepared in the same manner as in Example 2, except that 0.1 part by weight of a photoinitiator was used.

Comparative Example  2

Comparative Example 2 was prepared in the same manner as in Example 2, except that 15 parts by weight of a photoinitiator was used.

Comparative Example  3

Comparative Example 3 was prepared in the same manner as in Example 2, except that 0.2 part by weight of a photoinitiator was used.

Comparative Example  4

Comparative Example 4 was prepared in the same manner as in Example 2, except that pentaerythritol tetraacrylate containing a tetrafunctional acrylic group was used.

Comparative Example  5

55 parts by weight of 2-ethylhexyl acrylate, 40 parts by weight of methyl acrylate and 5 parts by weight of acrylic acid were added to a 1 L reactor equipped with a cooling device so that nitrogen gas was refluxed and temperature was easily controlled, After the mixed monomer mixture was added, 100 parts by weight of ethyl acetate (EAc) was added as a solvent. Then, nitrogen gas was purged for 1 hour to remove oxygen, and the temperature of the mixture was maintained at 55 캜. Thereafter, 0.05 part by weight of azobisisobutyronitrile (AIBN) diluted to a concentration of 50% in ethyl acetate as a reaction initiator was added to the mixture and reacted for 8 hours to obtain an acrylic copolymer resin having a weight average molecular weight of 800,000 Type).

0.05 parts by weight of an aziridine crosslinking agent was added based on 100 parts by weight of the solid content of the thermosetting acrylic copolymer resin produced in the above process. Thereafter, the mixture was diluted to an appropriate concentration, uniformly mixed, and then coated on a polyester release film to have a thickness of 70 μm after curing and dried to form a film having an adhesive layer. The film on which the adhesive layer was formed was laminated on both sides of 12 占 퐉 Black PET to prepare a double-sided pressure-sensitive adhesive tape.

The properties of the double-faced pressure-sensitive adhesive tapes of the Examples and Comparative Examples are summarized in Table 1 below.

Acrylic resin syrup Partial polymerization
Conversion Rate
(%) Viscosity
(cps) Photoinitiator
(Parts by weight) Bifunctional curing agent (parts by weight) Aziridine curing agent (parts by weight) Gel fraction
(weight%) Example 1 Type A 18 2000 2 0.03 - 40 Example 2 Type B 16 3000 2 0.03 - 40 Example 3 Type B 16 3000 5 0.03 - 36 Example 4 Type B 16 3000 2 0.08 - 45 Example 5 Type B 5 100 2 0.03 - 30 Example 6 Type B 20 10,000 2 0.03 - 50 Comparative Example 1 Type B 16 3000 0.1 0.03 - 60 Comparative Example 2 Type B 16 3000 15 0.03 - 20 Comparative Example 3 Type B 16 3000 2 0.2 - 70 Comparative Example 4 Type B 16 3000 2 0.03
(Tetrafunctional) - 60 Comparative Example 5 C type 16 3000 - - 0.05 60

evaluation

1. 180 ° peel force

The release films were removed from one side of the double-sided pressure-sensitive adhesive tape according to each of the Examples and the Comparative Examples, and 50 mu m of PET was laminated, and then a measurement sample having a width of 20 mm and a length of 250 mm was prepared. Each sample was attached to PC (polycarbonate), PMMA (polymethylmethacrylate), glass, and hard coated PC according to JIS Z0237 with a 2 Kg roller. Thereafter, the sample was stored for 30 minutes at a temperature of 23 ° C. and a relative humidity of 55%, and then peel strength was measured at a peeling rate of 0.3 m / min using a tensile tester. The results are shown in Table 2 below .

2. Endurance reliability

The peel strength measurement was carried out at 85 ° C and 85% relative humidity for 500 hours, and then the appearance was observed. The results are shown in Table 2 below.

180 ° peel force (gf / 25mm) Endurance reliability PC PMMA Glass Hard coated PCT PC Example 1 6500 6300 6500 5500 Good Example 2 6200 6100 6000 5700 Good Example 3 6700 6500 6600 6000 Good Example 4 6500 6200 6300 6000 Good Example 5 6500 6200 6500 5800 Good Example 6 6300 6100 6300 5800 Good Comparative Example 1 3000 2800 2900 2500 Good Comparative Example 2 8000 7000 7000 6500 Bubble generation Comparative Example 3 2500 2000 2100 1500 Good Comparative Example 4 2700 2100 2200 1700 Good Comparative Example 5 2500 2000 2000 1500 Bubble generation

As can be seen from the above Table 2, the examples according to the present invention show excellent adhesive performance and high endurance reliability.

On the other hand, when the content of the photoinitiator is low or the content of the hardener is high, it is confirmed that the endurance reliability is good but the adhesive performance is deteriorated. In contrast, when the photoinitiator content was high, it was confirmed that the adhesive performance was excellent but the durability was poor.

Claims (8)

materials; And an adhesive layer formed on both sides of the substrate and including an acryl syrup, a polyfunctional acrylic group-containing curing agent, and a photoinitiator,
The weight-average molecular weight of the acrylic syrup is 80,000 to 200,000,
The content of the polyfunctional acrylic group-containing curing agent is 0.01 to 0.1 part by weight based on 100 parts by weight of the reactive monomer of the acrylic syrup,
Wherein the adhesive layer has a gel fraction after curing of 30% by weight to 50% by weight.
The method according to claim 1,
Wherein the acrylic syrup comprises a (meth) acrylic ester monomer.
The method according to claim 1,
Wherein the acrylic syrup further comprises at least one selected from a polar monomer copolymerizable with the (meth) acrylic ester monomer, a chain transfer agent, and a reaction initiator.
The method according to claim 1,
Wherein the acryl syrup is partially polymerized at a conversion of 5 to 20%.
delete The method according to claim 1,
Wherein the acrylic syrup has a viscosity of 100 to 10,000 cps.
delete The method according to claim 1,
Wherein the content of the photoinitiator is 1 to 10 parts by weight based on 100 parts by weight of the reactive monomer of the acrylic syrup.

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